Biota of Lakes and Reservoirs - Hydro-Environmental Analysis: Freshwater Environments - page 423

Algae bloom on Grand Lake St. Marys We st
Beach on June 23, 2010

Grand Lake St. Marys June 2010 algal bloom

We st Beach recreational restrictions imposed on
Grand Lake St. Marys users on June 23, 2010

FIGURE 15.11 Cyanobacterial algal bloom and lake in Grand Lake St. Marys in western Ohio, 2010. (From
Davenport, T. and Drake, W., LakeLine , Fall, 41-46, 2011. Courtesy of the North American Lake Management
Society. With permission.)

the growth of other algae (which may be more palatable to zooplankton and better support overall
productivity). In addition, Cyanobacteria may produce toxins. The Lyngbya species produce a toxin
that results in what is known as “swimmer's itch” or cyanobacterial dermatitis. Three of the most
common and problematic organisms are in the genera Anabaena , Aphanizomenon , and Microcystis .
For example, the Cyanobacteria of the genus Microcystis releases the hepatotoxin microcystin
(Brittain et al. 2000; Vanderploeg et al. 2001), which is extremely toxic, causing death in livestock
and human health problems. The toxicity of three blue-green algae toxins (anatoxin, microcystin,
and aphantoxin) is compared to that of one of the deadly groups of mushrooms and the toxicity of
cobra venom in Table 15.2.
The World Health Organization established a recommended limit of 1 μg L−1 for drinking water
(Brittain et al. 2000; Vanderploeg et al. 2001), which can be exceeded many times in HABs. The

TABLE 15.2
Comparison of Toxicities of Three Cyanobacterial Toxins

Toxin Source LD50 ( μ g kg -1 )

Muscarine Amanita mushroom 1100

Anatoxin Anabaena 250

Microcystin Microcystis 60

Neurotoxin Cobra venom 20

Aphantoxin Aphanizomenon 10

Source: Smith, V.H., Blue green algae in eutrophic fresh waters, LakeLine ,
Spring, 34-37, 2001.
Note: LD50 is the dose required to kill 50% of laboratory animals receiving
the toxin.